Authentication Agent:
* Added `Show Token` function which allows a user to get the current authentication bearer token for use in other applications.
Upload Utility:
* Logout button action now also explicitly clears all session cookies.
* On app exit the user is provided with a prompt asking if they want to "completely logout" (clearing all session cookies, as above) or allowing session state to be cached. Allowing the session state caching bypasses the Globus Auth login form until the Globus Auth session state cookies expire.